Product Info

LTE Standard Module Series
EC21 Hardware Design
EC21_Hardware_Design 58 / 120
3.13. SD Card Interface
EC21 supports SDIO 3.0 interface for SD card.
The following table shows the pin definition of SD card interface.
Table 15: Pin Definition of SD Card Interface
Pin Name Pin No. I/O Description Comment
SDC2_DATA3 28 IO SD card SDIO bus DATA3
SDIO signal level can be
selected according to SD
card supported level,
please refer to SD 3.0
protocol for more details.
If unused, keep it open.
SDC2_DATA2 29 IO SD card SDIO bus DATA2
SDC2_DATA1 30 IO SD card SDIO bus DATA1
SDC2_DATA0 31 IO SD card SDIO bus DATA0
SDC2_CLK 32 DO SD card SDIO bus clock
SDC2_CMD 33 IO SD card SDIO bus command
VDD_SDIO 34 PO SD card SDIO bus pull up power
1.8V/2.85V configurable.
Cannot be used for SD
card power. If unused,
keep it open.
SD_INS_DET 23 DI SD card insertion detection
1.8V power domain.
If unused, keep it open.
The following figure shows a reference design of SD card.
Figure 25: Reference Circuit of SD Card Interface